摘要:

The general system of equations describing the smoothing of surface structure in solids under irradiation is formulated. It is shown that under real conditions the system can be reduced to a simpler form which has an exact solution. A general formula describing the smoothing of surface structure with time is derived. As a special case, this formula gives the evolution (smoothing) of the relief in the absence of radiation, which is associated with the difference in curvatures for different roughnesses. The physical reason behind the intensification of smoothing under irradiation is the difference between the positions of the centers of gravities for concentration profiles of vacancies and interstitials. The radiation gives rise to a new type of dependence of the rate of smoothing on the roughness parameters of the surface, which permits the experimental separation of the contribution from radiation to smoothing and simultaneously makes it possible to determine some parameters which are difficult to measure. ©1997 American Institute of Physics.

ISSN:1063-777X    

DOI:10.1063/1.593339

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

New classes of exact solutions of the Schro¨dinger equation with simple explicit analytic expressions for potential fields, energy levels, and wave functions of stationary states are considered. The solutions are discovered with the help of new original methods elaborated in the quantum theory of spin systems. The corresponding effective potentials are compared to similar models of soliton origin. The main attention is paid to peculiar phenomena such as quasi-exact solvability, potentials with multiple and flexible profiles, fourth-order extrema, finite-band spectra and structural transformations in energy bands, and the spin–soliton analogy. ©1997 American Institute of Physics.

ISSN:1063-777X    

DOI:10.1063/1.593340

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The Hamiltonian description of the motion of arbitrary discontinuity surfaces is proposed on the basis of the variational principle, taking into account the conservation laws in terms of consecutively introduced volume potentials (of the Clebsch type) as constraints. Such a method of introduction of Hamiltonian variables makes it possible to generalize the known canonical variables for the interface between two media to the cases of shock waves and slip surfaces. The results are compared with the introduction of surface Hamiltonian variables through the canonical transformations of bulk Hamiltonian variables. The results permit a direct generalization to the case of magnetohydrodynamics, plasmas, superfluid liquids, and other media for which the bulk Hamiltonian equations are known. ©1997 American Institute of Physics.

ISSN:1063-777X    

DOI:10.1063/1.593341

出版商:AIP    

年代:1997

数据来源: AIP